Valve and door assembly for semi-frozen food dispensing machine

ABSTRACT

A softserve product refrigeration and dispensing machine (1) having numerous novel features, including a novel door (80) and product dispensing apparatus (60) having features to inhibit condensation and to provide a product dispenser design which may be easily flushed with no retention of food stuffs and the like and configured to require minimal lubrication. The novel door assembly allows for sealing of the freezing chamber (17).

This application is related to 1) application Serial No. 09/265,689,filed on Mar. 10, 1999 and entitled “High Efficiency RefrigerationSystem”, and claims priority from 2) Provisional application Serial No.60/135,063, filed on May 20, 1999 and entitled “Semi-Frozen Food orBeverage Dispensing Machine”, and is related to a) copending applicationSer. No. PCT/US00/14005, filed on even date herewith and entitled“Improved Pre-Product Mix Cooling For A Semi-Frozen Food DispensingMachine”; b) copending application Ser. No. PCT/US00/13825, filed oneven date herewith and entitled “Improvements In Feeding And ControllingProduct Pre-Mix In Semi-Frozen Food Dispensing Machines”; c) copendingapplication Ser. No. PCT/US00/13781, filed on even date herewith andentitled “Apparatus And A Method For Clean-In-Place For A Semi-FrozenFood Dispensing Machine”; d) copending application Ser. No.PCT/US00/14029, filed on even date herewith and entitled “ImprovedBeater/Dasher For Semi-Frozen, Frozen Food Dispensing Machines”.

BACKGROUND OF THE INVENTION

The present invention relates to improvements in semi-frozen, frozenfood product or beverage refrigeration machines, and more specifically,relates to improved structures for improving the quality, consistency,and efficiency of operation while improving product yields and ease incleaning of machinery utilized in the manufacture and dispensing ofsemi-frozen, frozen food products or beverages.

Dispensing Door Construction

An important structure in a softserve product refrigeration machine isthe dispensing door construction, which usually also carries with it theproduct dispensing valve mechanism utilized for removing product fromthe freezing cylinder (evaporator). An ideal door would be one whichminimizes condensation so that it does not have to be continuouslyattended to by an attendant; one that provides an excellent seal for thefreezing cylinder when the door is closed; is designed so that the sealbetween the door and the freezing cylinder does not create anobstruction which catches the softserve product, or inhibits properdrainage of product/cleaning and/or sanitizing fluids therefrom when thefreezing cylinder is being cleaned. Many designs have utilized a flatgasket between the door and freezer, such as the Clifford patent (U.S.Pat. No. 3,050,960, issued on Aug. 28, 1962), which constructionrequires a high pressure being exerted to effect a proper seal. Otherdesigns have utilized an O-ring captured inside the freezing cylinderand projecting or protruding from the interior surface of the freezingcylinder. While an O-ring eliminates the need for high forces, itobstructs the proper drainage of product from the freezing cylinder. Inessence, the O-ring design requires that the product exit port be raisedabove the bottom edge of the freezing cylinder by an amount equal to thewidth of the O-ring seal. In this manner, it is difficult to provideproper drainage of product or cleaning and/or sanitizing fluids whencleaning both the door and the freezing cylinder. It should be mentionedthat U.S. Pat. No. 2,916,044, issued on Dec. 8, 1959, does illustrate acover and serving valve for freezers utilizing an insulation which isprimarily for inhibiting condensation due to the capturing of the retard(or baffle) in the cover.

Dispensing Valve Mechanism

Another important aspect of a properly designed softserve productrefrigeration machine is the dispensing valve mechanism. While valvemechanisms have varied, it is absolutely essential that the mechanism beeasy to clean. That is, the valve mechanism must have no physicalinternals which allow for food product retention such that it can beeasily cleaned by flushing with sanitizers. Valve designs which use aplunger with O-rings have small crevices between the moving parts wherefood product becomes lodged and is difficult to remove in the cleaningprocess. These designs, moreover, allow leakage of food product past theO-ring and this leakage of food product makes it incapable of effectivecleaning in a clean-in-place process. Moreover, this kind of design mustbe lubricated, which usually requires disassembly. Another desirablefeature of an ideal dispensing valve is that all product in thedispensing spout should be forced from the valve leaving no residualproduct to later melt and dip.

In order that the reader may better understand the nuances of thesoftserve refrigeration and freezing process, the following material istendered, and directed towards various ones of the copendingapplications set forth above.

Increasing Refrigeration Cycle Efficiency

Normally, semi-frozen, frozen confection food product or beverage(hereinafter “softserve product”) is drawn from a freezing cylinder orchamber (evaporator) at intermittent times. However, the product must bein a proper state for serving when it is needed. Conventionally, tomaintain product temperature and/or viscosity at an ideal state, themain refrigeration system is required to run quite frequently. Moreover,dependent upon the draw of the softserve product, additional quantitiesof product mix, usually kept at a refrigeration temperature below 41degrees Fahrenheit to prevent spoilage, requires an increase draw ofsuch mix, proper aeration or “overrun”, which of course, creates furthercycling of the main refrigeration system.

Numerous attempts have been made to reduce this refrigeration systemrecycling so as to increase the efficiency of the system. For example,in U.S. Pat. No. 5,386,709 (issued on Feb. 7, 1995), methods andapparatus are disclosed for incorporating thermal storage and other lowtemperature reservoirs with a secondary or retrofitable refrigerantcircuit to increase the thermal operating capacity and efficiency bysubcooling refrigerant condensate with subcoolers. However, auxiliarypower equipment is required, once again lowering the overall systemefficiency making it undesirable for softserve product dispensingrefrigeration machines. In other systems, such as in U.S. Pat. No.4,643,583 (issued on Feb. 17, 1987), a eutectic liquid is introducedinto a space intermediate an inner metal vessel and an outer case. Thepurpose of the provision of a eutectic liquid is purportedly to maintainthe vessel at a nearly constant temperature so as to ensure whisking (orcommonly referred to as scraping) of the ice cream mixture within thecold storage container. But this system also requires a secondrefrigeration system in order to maintain the container at the whiskingtemperature.

During the transition from active freezing of the product to the idlestate of the refrigeration system, the temperature of the evaporatormust be raised to prevent “sticking” of the scraping or beater bladesupon subsequent restarts. To accomplish this, the evaporationtemperature should be preferably raised to within a few degrees of theproduct temperature. In this manner, “sticking” of the scrapers on thenext restart does not occur. This is accomplished in the novel softserveapparatus by a novel method and means without necessitating a secondrefrigeration system.

Overrun

It is well-known that it is essential for consistency of softserveproduct that an amount of gaseous matter such as air should beincorporated into the liquid ice cream mix at the time of freezing.“Overrun”, which is defined as a percentage, may be determined in anumber of ways, one such way is:$\left( {\frac{W_{L}}{W_{P}} - 1} \right) \times 100$

W_(L)=Weight of volume (test) of raw liquid mix

W_(P)=Weight of an equal volume of product (including air)

Overrun is accomplished either with a feed tube and air orifice in agravity style freezer, such as illustrated in U.S. Pat. No. 5,706,720(issued on Jan. 13, 1998) or a pump in a pressurized freezer. The feedtube method does not provide accurate control of overrun because theliquid fill rate is dependent upon the mix level in the hopper and theair flow rate is affected by “barrel” pressure. Thus, when product isbeing dispensed from the freezer, a pressure drop is sensed in thebarrel (the feed tube or conduit which supplies applying mix and air tothe freezer unit) changing the overrun percentage. Thus, with this typeof apparatus, at best, a limited overrun range is provided and it isdifficult to control the percentage (%) of overrun.

In a pressurized freezer, a pump is employed which provides somewhatimproved accuracy allowing for a greater range of overrun but requiresphysical component change to vary the overrun settings. Moreover, thepump also adds a degree of complexity to the freezer operation becauseof the number of components that must be cleaned, lubricated andreassembled. Once more, the control of overrun by the pump is effectedby the draw rate of the softserve product. Since the pump is a positivedisplacement device for the liquid portion and a pressure sensitivedevice for the air portion, while the liquid mix flow rate is notaffected by changes in barrel pressure, which can vary with the drawrate, the air flow rate, being pressure sensitive, will vary as thebarrel pressure changes. Such a system is shown in U.S. Pat. No.4,457,876 (issued on Jul. 3, 1984). Once again, it would be desirable toprovide a system which would allow control of overrun by an accuratesetting of the overrun. Moreover, the system provided should be easilycleaned, preferably without removing or disassembling the system such asnecessary with a pump system.

Beater or Scraping Blades

Once the mix and proper air mixture has been fed into the freezer, it isvital that the mix be moved or beaten so that a continuous folding orblending of the nearly frozen mixture occurs in the freezing cylinder,and that the material as it freezes in the freezing cylinder is whiskedor scraped off and dropped back into the mix for further blending andmovement within the cylinder. Most beater designs have involved aframework of stainless steel bars and castings. In fabrication, thesedesigns required a large amount of welding or brazing to complete themanufacture. Moreover, welding oftentimes proves to be less sanitarythan desired and the brazing operation also lacked compatibility withhighly acidic mixes. While there have been many designs recommended forbeater construction (see Re. 32,159 of May 27, 1986, which utilizesinsertable blades), and the design illustrated in U.S. Pat. No. 512,002(issued on Jan. 2, 1894), all of these designs require massiveconstructions and are difficult to fabricate in order to arrive at astrength sufficient to be able to properly fold or beat the softserveproduct. What is required in a properly constructed beater assembly isnot only great strength (because the softserve product, such as a frozenconfection e.g., softserve ice cream, is very stiff and offers highresistance to the rotation of the beater assembly or dasher) but alsosomething that is easy to construct, will give better blending of themix within the freezing chamber, and therefore give a consistentlyhigher quality product at a higher throughput.

Mix Level Sensing

In an ideal softserve product refrigeration machine, it is desirable toprovide a simple method for sensing the level of mix so that theequipment operator may be forewarned when the mix is almost depleted, aswell as to inform him periodically as to how much mix is left in theproduct feed conduit to the freezing cylinder. Numerous prior artsystems have been employed for level and/or amount sensing. For example,in U.S. Pat. No. 4,386,503 (issued on Jun. 7, 1983), pressuredifferences are used to regulate the supply of liquid P₂S₅ which allowsfor measurement of the liquid level in the device with respectivepressure differences being utilized for regulating the supply of theliquid P₂S₅ to the cooling device. In this manner, a predeterminedliquid level may be maintained. Moreover, patents such as U.S. Pat. No.3,646,774 (issued on Mar. 7, 1972) utilize pressure sensitive switchesfor measuring material levels, while patents such as U.S. Pat. No.4,417,610 (issued on Nov. 29, 1983) utilize some kind of pressure sensorlocated up stream of an outlet valve for effectively adjusting a lengthof the opening time interval as a function of a variation of an averagemedium pressure between consecutive operations of operating cycles ofthe outlet valve arrangement.

Clean-in-place (Cleaning of the Machine)

Conventionally, softserve machines require daily cleaning and/orsanitizing to insure that undesired bacteria and the like areeliminated. Because of the intricate parts of such machines,traditionally the machines must be disassembled and each part thatcontacts food thoroughly decontaminated and cleaned. The machine is thenreassembled. This process can require trained personnel and personalattention several hours a day. Moreover, this procedure usually occursafter normal operation hours requiring overtime or additional personnel.What has long been desired, is a machine design which allows for“clean-in-place” and employs a method of cleaning that is reliable andsafe, is quick and which does not require disassembly and reassembly ofthe machine while insuring cleanliness of the machine. That isaccomplished by a softserve product refrigeration machine disclosedherein. As will be seen, special machine construction allows forcomplete “clean-in-place” operation without disassembly of the machinefor cleaning.

Softserve Product Refrigeration Machine Operation & Control

A principal limitation of existing softserve product refrigerationmachines is that they are setup “tuned” to run well under a typical setof environmental variables. Examples of these variables would betemperature, humidity, mix composition, power (electrical) quality, andthe manner that the operator uses the machine. Whenever the machine isoperated outside of the median point of these parameters (and others)the product quality suffers, in most cases not to a large degree butsuffers nonetheless. In general the systems in use today must live withthis loss. What is preferable, and what is accomplished advantageouslywith the softserve machine described herein, is a fully integratedsystem of mechanical and refrigeration hardware, electronic hardware,and software. This full integration allows each portion of the machineto perform functions that are best suited to that particular technique.

SUMMARY OF THE INVENTION

In view of the above, a principal advantage of the present invention isthe novel dispensing door assembly for the freezing chamber or cylinder.To this end the assembly ensures tight closing of the freezing cylinderat the end thereof from which product egresses the freezing cylinder,and which, in conjunction with the novel cover design and interlockingdispensing valve design, ensures good locking action of and closing offof the freezing cylinder. Moreover, the advantage of the special coverdesign for the door not only ensures interlocking with the productdispenser to prevent inadvertent displacement of the door, but alsoinhibits condensation, which normally would occur because of the hightemperature difference between the freezing cylinder and the atmosphereoutside of the dispensing valve and door. To achieve these advantages,the freezing chamber includes a tube having a rim at one end thereof,the door assembly including a door, including alignment lugs on one ofthe door and the rim, and apertures, intended for reception of the lugson the other of said door and rim, to ensure proper alignment of thedoor with the rim. An annular projection on one of the door and rim andan annular receptacle on the other of the door and rim, align when thedoor is in position in mating engagement with the rim. The inclusion ofa Z-shaped (in cross section) seal fittable in the receptacle (with adepending radial extending lip) serves to receive the annularprojection, the cup providing a radial seal and the lip providing anaxial seal therewith. The cover member has an exterior and interiorportion, the interior portion having a door engagement portion to causepressing engagement between the door and the rim. A locking collar onthe exterior portion of the cover provides locking engagement with therim of the freezing cylinder, the major portion of the interior portionof the cover being spaced from the door to form an insulating air spaceto inhibit condensation.

Yet another advantage of the present machine structure is the ability tomaintain the cleanliness of both the freezing cylinder and theassociated door, cover and dispensing valve. To this end, a passagewayin the door receives product from the freezing cylinder forcommunication with a product outlet from the door. A receptacle forinsertion into the door is in a path aligned with the product outlet anda product dispensing valve is disposed in the receptacle. An aperture inthe cover is aligned with the receptacle and engageable thereby, inconjunction with the valve, to retain and lock the cover to the door.The structure of the dispensing valve facilitates cleaning in situ. Tothis end, the dispensing valve includes a piston and a seat for thepiston in the door in the product outlet, and a rolling diaphragmcarried by the piston seals the receptacle from product whether thepiston is either in a position to dispense product or is sealing theproduct outlet. In this manner, as the dispensing valve is open fordispensing the softserve product from the refrigeration machine, thediaphragm connected to the head end rolls with the upward movement ofthe piston leaving no cracks or crevices for the retention of unwantedproducts. Additionally, the openings allow for cleaning in situ of boththe passageway and the dispensing outlet from the door, facilitating themaintenance of cleanliness of the machine.

Another advantage of this kind of dispensing valve for the softserveproduct is that a rolling diaphragm valve neither requires lubricationto keep it active nor periodic disassembly to lubricate. Moreover, byproviding a novel flush system, such hard to get parts and places, suchas the drive attachment to the beater, may be cleaned in situ.

The overall machine structure also provides numerous advantages. Forexample, the present softserve machine provides the advantages of aclosed refrigeration system having a recirculating refrigerant path, thesystem including the conventional condenser having a liquid refrigerantoutput, a throttling expansion valve for changing the state of therefrigerant to a gas, and an evaporator serially connected in therefrigerant path. A subcooler is placed intermediate the condenser andthe throttling expansion valve, the subcooler having a primary andsecondary side. The primary side of the subcooler is in the path of thehigh-pressure liquid refrigerant from the condenser, and a path ofgaseous refrigerant is supplied from the outlet of the evaporator to thesecondary side of the subcooler, in heat exchange relation with theprimary side. A heat sink in the subcooler is placed in heat exchangerelation with both the primary and secondary sides of the subcooler. Atap on the liquid side of the refrigeration path, from the subcooler,forms a secondary refrigeration path for cooling a product mix containerwith a refrigeration coil therein so as to maintain the product mix at apredetermined temperature. The heat sink in the subcooler increases theefficiency of the system, reducing cycling of the refrigeration system,while having the ability to transfer heat out of the subcooler when thesystem is running and absorb heat so as to reduce the running cycle ofthe refrigeration system when the system is idle. This permitslengthening times or periods of passive cooling and advantageouslyeliminates the requirement of a separate active refrigeration system forthe product mix cabinet.

Another advantage of the present softserve machine is the ability toconsistently provide a predetermined mixture of product mix and agaseous medium (e.g., air) to a freezing chamber of a softserve productrefrigeration machine. This is accomplished by providing a pressurizedmix container that is connected to a source of pressurized gas (e.g.air) connected to the gas or air supply inlet of the pressurized mixcontainer. A product mix outlet from the pressurized container, in theform of a conduit, connects the pressurized mix container to thefreezing cylinder of the softserve product refrigeration machine. Thepressurized gaseous matter, at the same pressure as applied to the mixcontainer, is also applied to a gaseous matter (air) injection point inthe conduit to affect mixing of gas (air) and product mix before entryof the mix into the freezing chamber. By introducing a pressure adjuster(e.g., a needle valve) in the line, the ratio of gas (air) to mix may beclosely regulated so as to control “overrun.”

Still another advantage of the present apparatus in a softserve machineis the ability to determine the amount of mix left in the pressurizedmix container. This is accomplished by including a gas/air pressure dumpvalve intermediate the source of pressurized gas/air and the gas/airsupply inlet of the mix container. The dump valve is controlled toisolate the source of pressurized gas/air from the mix container andallows the dumping of gas/air from the mix container for predeterminedperiods of time. The change of pressure per predetermined time of thegas/air dump indicates the quantity of mix left in the mix cabinet.

Another advantage of the apparatus of the present structure is that asimple instrument may be provided to determine when the mix is entirelygone from the pressurized mix container. To this end, an instrument,such as a thermal probe having a thermister or the like therein, may beplaced at the injection point at the conduit. This means the probe ispreferably placed in the mix line feeding the air/mix chamber or barrel.By forcing a small electric current through the thermister probe, as thethermister has an impedance, the current creates heating of thethermister. When mix is present, the liquid mix rapidly dissipates theheat of the thermister. But when all the mix is depleted, the thermalconductivity surrounding the probe is reduced and the thermister becomeswarmer. This rise in temperature can be electrically sensed by thecontrols as the resistance of the thermister diminishes with risingtemperature. In this manner, the control detects the presence or absenceof a liquid mix.

Another distinct advantage of the apparatus of the softserve machine isa new beater assembly design (commonly called a dasher in the softserveproduct refrigeration machine art). The advantages of high-strength andease of construction while maintaining better blending and consistencyof product as well as increased throughput all lend themselves to a moreefficient machine for dispensing softserve product. To this end, thebeater assembly comprises a foraminous tube without any welded parts.The front helical portion of the beater, which forces product out of thefreezer through the dispensing valve (product pushing helical member),is preferably made of an easily cleaned plastic which is readily moldedand inserted, as by key ways, into one end of the foraminous cylinder.The scraping elements of the dasher or beater are also preferablycomposed of a material, such as a plastic, for whisking or scraping theinterior surface of the freezing cylinder. These scraping elements maybe provided with a snap type fitting which allows them to be snappedinto place in appropriate places on the cylinder. Preferably, thescraping elements should be biased toward the interior of the freezingcylinder to compensate for wear of the scraping elements due to rotationwithin the freezing cylinder. The driving portion of the foraminouscylinder includes a baffle rod for non-driving engagement at one endwith a rotatable drive shaft (for effecting rotation of the foraminouscylinder) and at the forward end with the door assembly or other meansto inhibit rotation of the baffle rod. The baffle rod is positionedwithin the cylindrical beater (foraminous cylinder), and is eccentric tothe centerline of the beater, and mounted so as to be stationary withrespect to beater rotation. The baffle rod may include foraminous hubsor elements through which mix is forced, helping to insure a goodblending of the mix in the freezing cylinder.

Still another feature of the present machine is the provision of acontrol for the machine which facilitates hands-off operation andadjusts the machine, regardless of the draw-down of the product, toinsure the quality of the product.

Other advantages and features and a more complete understanding of theinvention may be had by reference to the following specification andclaims taken in conjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a semi-frozen, frozen food or beveragedispensing (“softserve”) machine constructed in accordance with variousadvantageous features including those of the present invention;

FIG. 2 is an exploded perspective view of the machine illustrated inFIG. 1 and showing selected parts of the softserve machine displaced toillustrate generally their relative placement;

FIG. 3 is a schematic diagram of an improved refrigeration systemutilized in the softserve machine illustrated in FIGS. 1 and 2, andemploying a subcooler with contained heat sink, and auxiliary, tappedcooling system for product mix to achieve greater efficiencies inoperation of softserve product refrigeration machines;

FIG. 4 is a schematic diagram illustrating a method and apparatus forapplying product mix to the freezing cylinder with the proper amount ofoverrun, as well as illustrating how gas (e.g., air), from a commonpressurized source, may be injected into the barrel of the product mixbeing provided to the freezing cylinder;

FIG. 5 is a fragmentary schematic view of the apparatus illustrated inFIG. 4 and in which the valves are positioned to permit cleaning of theapparatus;

FIG. 6A is an exploded view illustrating a portion of a novel doorassembly of the illustrated machine, and how it coacts with the bafflerod associated with the beater of the freezing cylinder as well as thehousing of a novel valve assembly;

FIG. 6B is an enlarged, fragmentary perspective view of the interior ofthe door assembly shown in FIG. 6A with a receptacle therein to captureone end of the baffle rod to inhibit rotation thereof with rotation ofthe beater;

FIG. 7 is an exploded view illustrating the door assembly of thesoftserve machine and showing the parts necessary for proper matingcoaction of the door with the freezing cylinder;

FIG. 8 is an enlarged end elevation view of the door assemblyillustrated in exploded fashion in FIGS. 6A-7;

FIG. 9 is an enlarged fragmentary sectional view taken along lines 9—9of FIG. 8;

FIG. 10 is a fragmentary, side elevational view of a novel beater ordasher assembly constructed advantageously for the softserver machine,and in position in the freezing cylinder for being rotatably driven by amotor including novel shaft sealing for facilitating sanitary flushingof the apparatus;

FIG. 11 is a fragmentary sectional view taken along line 11—11 of FIG.10;

FIG. 12 is a fragmentary sectional view taken along line 12—12 of FIG.10;

FIG. 13A is a fragmentary sectional view taken along line 13—13 of FIG.10;

FIG. 13B is an enlarged fragmentary sectional view of a portion of aseal and shaft illustrated in FIG. 10;

FIG. 14A is an enlarged, perspective view of another novel beater ordasher assembly constructed for advantageous operation in the softservemachine;

FIG. 14B is an enlarged perspective view of a scraper blade used in thebeater/dasher of FIG. 14;

FIG. 14C is a fragmentary sectional view taken along line 14C—14C ofFIG. 14A;

FIG. 15 is a state diagram illustrating the general software structureand requirements for the basic mode of operation of the softservemachine;

FIG. 16 illustrates a state diagram of the power-up mode of thesoftserve machine;

FIG. 17 is a state diagram illustrating the priming mode in which rawproduct is first brought into the machine;

FIG. 18 is a state diagram illustrating the initial freeze down mode inwhich the raw product is frozen for the first time;

FIG. 19 is a state diagram illustrating the state of the softservemachine when the product is in a product ready mode and being maintainedin that state by utilizing passive cooling in order to keep the productnear a predetermined quality for as long as possible;

FIG. 20 is a state diagram illustrating the softserve machine in anactive product maintenance mode, when the product has become too warmand/or has been allowed to sit in the barrel of the softserve machineand requires re-freezing and more gas (air) to be incorporated into theproduct mix;

FIG. 21 is a state diagram illustrating the softserve machine in a cleanin place mode;

FIG. 22 is a block diagram of the overall system for controlling theoperation of the machine in the various states depicted in FIGS. 15-21;

FIG. 23 is a block diagram of the main system control board;

FIG. 24 is a block diagram of the input/output board for controlling thepower supplied to various boards in the system;

FIG. 25 is a block diagram of a clean-in-place (“CIP”) board employed inthe system for controlling the operation of the machine duringclean-in-place operations,

FIG. 26 is a block diagram of the refrigeration mix control boardutilized for maintaining the temperature, humidity and the like for themix cabinet; and

FIG. 27 is a block diagram of the Data Logger and Communications Boardwhich permits and facilitates, as its name implies, data recordation andcommunications between the control system and the outside world.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Overall Description ofthe Machine

Turning now to FIG. 1, a semi-frozen, frozen food or beverage dispensing(“softserve”) machine 1, constructed in accordance with various featuresof the present invention, is illustrated therein. As shown, thesoftserve machine 1 includes a cabinet 1 a including top and side panels2 a and 2 b including respectively an air deflector 1 b and side vents 1c. The front 3 of the machine 1 comprises a softserve product dispenseror product dispensing valve assembly 60, and manually operable handle 61thereon to permit the operator to draw softserve product through thevalve assembly 60, in a manner to be described more completelyhereinafter. As is typical in this kind of machine, a drip tray 4,including a product splash shield 5 is positioned below the productdispenser or valve assembly 60.

Just above the drip tray 4 is a door 40 a which allows operator accessinto a refrigerated mix storage cabinet or compartment 40 (see FIG. 2).In use, the cabinet 40 houses a pressurized product mix container 43which provides product mix, in a novel manner, which will be explainedhereinafter, to the freezing cylinder 17 of an evaporator 16. A noveland efficient beater (or dasher) 110 including a foraminous sleeve orcylinder 112 serves to agitate and mix the product within the freezingcylinder 17 and allow for product mix uniformity and consistency. Acontrol and display panel 150 displays system conditions and allows foroperator control over at least selected ones of them.

THE REFRIGERATION AND SUBCOOLER ARRANGEMENT

Turning now to FIG. 3, a main refrigeration system 10 includes acondenser 12, a throttling expansion valve 14, an evaporator 16 and acompressor 18. As shall be described more completely hereinafter, asubcooler 30 has a primary refrigerant flow circuit disposed in theprimary side of the refrigerant path (high pressure side as indicated bythe arrows 8 a which show high pressure refrigerant flow), and having asecondary refrigerant flow circuit disposed in the low pressure side ofthe refrigerant flow circuit, as indicated by the direction ofrefrigerant flow arrows 8 b.

As illustrated in FIG. 3, a tap 19 is formed in the high pressure sideof the refrigeration system before the throttling and expansion valve14, to provide a flow of refrigerant to the refrigerated mix cabinet 40as through a first solenoid valve 21 a and conventional capillary tube22 (which acts as a throttling/expansion valve). As shown, therefrigerated mix cabinet 40 operates in parallel with the evaporator 16,and as shall become apparent, is aided in being maintained at its properpre-mix temperature by operation of the subcooler 30. The refrigerantpasses through refrigeration coil 41 and the gaseous mixture follows thepath as given by the refrigerant path arrow 8 c, past an evaporatorpressure regulator or EPR valve 23. The EPR valve 23 controls backpressure in the mix cabinet 40. The output of the EPR valve 23 joins theevaporator 16 gas output at junction 23 a. The gaseous refrigerantoutput from the evaporator 16 passes through a check valve 16 a, asecond solenoid valve 21 b, to the junction 23 a to the subcooler 30 andthen through the subcooler 30 to the suction side of the refrigerationcompressor 18. The second solenoid valve 21 b controls refrigerant flowfrom the evaporator 16.

The subcooler 30 is provided with a heat sink comprising a canister 32of an adjustable phase/state solution, such as a glycol/water mixture sothat the canister 32 will dispel heat during the main cooling cycle ofthe soft serve freezer or evaporator 16, whereby a steady residualcooling may be effected thereby during periods of low or no product drawfrom the product dispensing valve 60. Normally, product is drawnintermittently from the soft serve freezing cylinder 17 but must be in aproper product serve state when the product is needed. To maintain theproduct in an optimal state for serving at all times, the mainrefrigeration system is normally run quite frequently. (Moreover, asmore fully explained hereinafter, the temperature and internal pressurewithin the freezing cylinder 17 is monitored and controlled by acontrols/control system 55, as through monitor and control lines 17 d.)This frequency of runs or run cycles may be reduced by providing areserve supply of partially frozen solution such as glycol solution inthe container 32 during the run periods. The partially frozen glycolwill then act as a heat sink during the off periods thus providingcontinued cooling to both the softserve product and the auxiliary mixstorage cabinet 40. This is accomplished without the addition of anyspecial components since the refrigerant in the system condenses at thecoldest surface within the system and maintains a pressure equivalent tothe vapor pressure at that point. Liquid refrigerant is supplied, asneeded to the capillary tube 22, and then as gaseous refrigerant to thecoil 41 of the mix cabinet 40 so that cooling will continue. As long asthe frozen glycol (as monitored by control line 30 a) remains colderthan the product mix in the mix cabinet 40, (as monitored by the controlline 40 a) the glycol will continue to draw heat from the mix cabinet.(Moreover, dependent upon the control of the backpressure in theevaporator by the valve 21 b, heat may also be drawn from the evaporator16). The check valve 16 a in the refrigerant outlet side of theevaporator 16 ensures that heat drawn from the mix cabinet 40 via thegaseous refrigerant is drawn to the glycol canister 32. The glycolcanister 32 is preferably and conveniently enclosed within the subcoolerto obtain maximum efficiency. In practice, the container may holdapproximately two quarts of a glycol/water solution to achieve goodresults in a small system by reducing the cycling of the refrigerantthrough the refrigeration cycle.

It should be recognized that the utilization of a subcooler increasesthe refrigeration efficiency of the system and permits of greaterutilization of a smaller evaporator or freezing cylinder 17. Moreover,by proper operation of the control/control system 55, and predeterminedoperation of the valves 21 a and 21 b through control line 21 c and 21 drespectively, while controlling active refrigeration, for example bycontrol of the compressor 18 through control line 18 a, passive coolingby the subcooler operates to increase the possible off time of thesystem. Additionally, as shall be seen in the portion of thisspecification describing the modes of operation of the control system55, product draw down (removal of semi-frozen product from theevaporator or freezing cylinder) can be used to cause the refrigerationsystem to become active (e.g., cause the refrigeration compressor 18 tocycle on) and of course non-active (e.g., cause the refrigerationcompressor 18 to cycle off) via control line 18 a.

METERING ASSEMBLY

As noted heretofore, the interior of the evaporator 16 illustrated inFIGS. 2 and 10, is normally referred to as a freezing cylinder 17.Interiorly of the freezing cylinder 17 and mounted for rotation therein,is the dasher or beater assembly 110. (It is noted at this juncture inthe description, that another embodiment of the beater or dasherassembly 610 is shown in FIG. 14, either assembly being acceptable andinterchangeable, one with the other). However, referring first to FIG.10, the beater 110 is connected to a shaft 111 which in turn is suitablyconnected to drive means, in the illustrated instance a motor 25 toeffect rotation of the beater or dasher. At the opposite end of thefreezing cylinder 17 is located a door assembly 80, which will be morefully described relative to FIGS. 8 and 9, and which includes a productdispensing valve 60, (see FIGS. 2 and 9), the dispensing actuator orhandle 61 of which is illustrated as being mounted in the door assembly80.

The product mix to charge the freezing cylinder is normally a liquidproduct mixture. However, it should be recognized that the chargingmixture can be a pellet and liquid mix or any other pre-mix whichpermits feeding of the mix into the freezing cylinder and allows forproper air entry into and entrainment within the mix. Turning to FIG. 4,in order to provide the proper amount of gas (e.g., air, and hereinafterreferred to as air) for incorporation into a product mix (e.g., liquid)softserve at the time of freezing within the freezing cylinder 17,apparatus is provided to properly meter the air into the mix in a mannerwhich allows consistency of the mix to air ratio. (It should berecognized that in conventional mix preparation into the freezingcylinder 17, air is the gas mainly employed. However, it should also berecognized that other gas mixtures may be supplied in lieu of air, forexample, to add flavoring, etc.). This mixture or ratio is referred toas “overrun” expressed as a percentage as to a predetermined volume ofliquid product mix versus the weight of an equal volume of product.Since the equal volume of product will of necessity include air, itsweight is going to be less than the weight of an equal volume of mix. Ashas been explained heretofore, the control of overrun may beaccomplished with a gravity feed tube and air orifice with a gravitystyle freezer. Alternatively, a mix feed pump may be employed for apressurized freezer. The feed tube method does not provide accuratecontrol of the overrun due to the liquid fill rate being dependent uponmix level in the hopper, and the air flow rate being affected by thepressure in the “barrel” (which is the portion of conduit or piping 26which feeds a mixture of air and liquid mix into the freezing cylinder17). While the gravity or feed tube method provides a limited overrunrange, the pump type system provides improved accuracy while allowingfor a greater range of overrun but requires physical component changesto vary the overrun setting. Moreover, such structure adds a degree ofcomplexity to the freezer operation because of the number of componentsthe operator must clean, lubricate and reassemble. Additionally, becausea positive displacement pump is utilized in pressurized systems, whichis employed for the supply of the liquid portion of the mix, and apressure sensitive device for the air portion, the control of overrun isdifficult. That is, the only thing that will change in the barrel 26will be the air flow rate because it is pressure sensitive. Thus, duringproduct draw, down pressure variations can occur causing changes in theamount of air provided to the product mix creating inconsistent andunpredictable product mix overrun.

This problem has been resolved by providing a product mix (e.g., liquid)and air delivery system which provides a product mixture and entrainedair mix at a rate which are both pressure sensitive, such that when thedraw rate of the product varies, causing a variation in pressure withinthe barrel, both the liquid delivery rate and the air delivery rate willchange proportionately maintaining a constant ratio of air to liquid.

To this end, a source of pressurized air, in the illustrated instance anair compressor 25 a is connected through a check valve 26 a to a threeway, solenoid operated dump valve 27. A suitable relief valve 26 b isprovided intermediate the check valve 26 a and the three way valve 27.The output of the three-way valve 27 is to a pressure transducer 28, andthrough a conduit line or pipe 29 a, through the mix cabinet 40, intothe air inlet 42 of a pressurized mix container 43. The air pressure ismonitored and the pressure transducer set as by control line 28 aconnected to the controls/control system 55. Liquid product may beprovided into the pressurized mix container 43 to provide a level ofproduct mix in the container 43, or the mix may be provided in the formof a collapsible, flexible bag 44. As shall become clear in the portionof this specification discussing clean-in-place, the container 43 or thecollapsible, flexible bag 44 may be filled with a cleaning and/orsanitizing liquid for cleaning the system, in lieu of product mix. Themix bag or mix container 43 contains a product outlet 45. To facilitatecleaning, it is preferable that the mix container 43 is removable fromthe mix cabinet 40. As pressure builds up in the pressurized mixcontainer 43, product mix is displaced through the outlet 45, throughpiping 46 to a tee 47, one pipe 47 a of which provides the product mixthrough a check valve 48 to the barrel 26, and ultimately the freezingcylinder 17.

As illustrated in the drawings, a tee 30 splits the air output line intoconduits or piping 29 a and 29 b. Thus the same air pressure exists inlines 29 a and 29 b both being provided by the source of air or aircompressor 25 a. The air from the tee 30 passing through line 29 bpasses a pressure adjuster 32, in the illustrated instance a needlevalve or the like which allows for adjusting the air pressure in theline extension 29 c following the needle valve. Another solenoidoperated three way valve 33 in the line 29 c and a check valve 34 allowsair to be injected into the barrel 26 at an air injection point 35. Thusthe air source provides pressure for both the mix container and the airto be metered into the product. This ensures that both product supplyand air feed are at an identical pressure level to inherently yield aconsistent ratio of air-to-mix. The pressure adjuster 32 also acts toadjust the amount of air delivered. The check valves, both 34 and 48,serve their obvious purpose to prevent mix from traveling back up to thepressure adjuster or needle valve 32 while the check valve 48 preventsair from being injected backward through the air outlet 45 into the bagof mix or into the liquid in the pressurized mix container 43. It shouldbe noted that the position of the three way valve 33, in FIG. 4, when itis in a first position, inhibits mix in line 46 from entering into theair supply line from pressure adjuster or needle valve 32 whilepermitting air flow to the barrel 26 in the path above identified.

A second solenoid operated two-way valve 133 is shown as tapped offbetween the three way dump valve 33 and check valve 34, and in thenormal mix and air supply mode, such as illustrated in FIG. 4, has onlythe function of allowing a series connection of air from the pressureadjuster or needle valve 32, through the three way valve 33 to the checkvalve 34. However, the purpose and use of two way valve 133 shall becomeevident with respect to a discussion of the clean-in-place (CIP)description relative to FIG. 5. Suffice at this point, that the valve133 is also under control of the controls/control system 55 as by way ofcontrol line 133 c.

The refrigerated mix cabinet 40, in which the pressurized mix container43 is housed, includes a conventional door 40 a which includes a safetyinterlock to prevent opening the mix container 43 when under pressure.This is accomplished by feeding a signal along signal line 50 to acontrols/control system 55, which in turn through signal line 27 achanges the operation of the solenoid operated three way dump valve 27and allows pressure inside the pressurized mix container to dump throughline 29 a and backwards through the dump valve 27 to the atmosphere.Dump valve 33, which has been set by controls/control system 55 by wayof signal line 33 a, is positioned into a second position to now preventthe air supply from progressing into the barrel 26, and inhibit furtherpassage of mix from line 46 into the barrel 26 through check valve 48.At the same time that the three-way dump valve 27 is placed in the dumpposition the compressor air flow to the mix container 43 is stopped dueto the dumping action of the valve 27. Alternatively, or in connectionwith the forgoing, the controls/control system 55, through signal line50 a may shut off the air compressor 25 a. Moreover, since the three-waydump valve 27 dropped the pressurize in the mix container 43, the door40 a may be safely opened by the operator as signaled by the controlline 50, disengaging the door interlock.

CLEAN-IN-PLACE (CIP)

Conventionally, softserve machines require daily cleaning and/orsanitizing to insure that undesired bacteria and the like areeliminated. Because of the intricate parts of such machines,traditionally the machines must be disassembled and each part thatcontacts food thoroughly decontaminated and cleaned. The machine is thenreassembled. This process can require trained personnel and personalattention several hours a day. Moreover, this procedure usually occursafter normal operation hours requiring overtime or additional personnel.What has long been desired, is a machine design which allows for“clean-in-place” or clean-in-situ and employs a method of cleaning thatis reliable and safe, is quick and which does not require disassemblyand reassembly of the machine while insuring cleanliness of the machine.

To this end, and referring now to FIG. 5, in lieu of the bag 44 of mixcontained in the pressurized mix container 43, the pressurized mixcontainer may be provided with a quantity of cleaning and/or sanitizingliquid or the like for direct pressurization thereof and ejectionthrough line 46. Alternatively, and as illustrated in FIG. 5, a bag 44of liquid sanitizer may be placed in the mix container 43 so that whenthe container 43 is pressurized, cleaning and/or sanitizing liquid isforced out of the bag and into line 46. Once again, operation of thethree-way dump valve 27 will allow application of air pressure from theair compressor 25 a, through the line 29 a, and of course into thepressurized mix container 43. The operation of the solenoid operatedthree way dump valve 33, as illustrated in FIG. 5, cuts off the airnormally supplied by the valve 33 to the line 29 c and check valve 34.By its position, it now is set as a “wash valve” which also now allowsflushing with cleaning and/or sanitizing liquid and the like, the aircheck valve 34 and the mix check valve 48 merely by forcing cleaningand/or sanitizing solution through line 46, past tee 47, through lines46 a, 47 a and the valve 33, into the barrel 26 and then into thefreezing cylinder 17 through the product mix inlet 26 c. As may be seenfrom the forgoing description, the “wash valve” on setting of the threeway dump valve 33 enables easy flushing of the lines and valves normallyexposed to the product mix with cleaning and/or sanitizing liquid Whilethe three-way dump valve 27 may be located in the position shown inFIGS. 4 and 5 if a bag 44 is employed, if the liquid product mix isemployed directly into the pressurized container 43, the dump valve 27should be relocated to the pressurized container 43 so that thepressurized line into the container does not back up with mix, andbecome contaminated, when the air supply line gets dumped.

The cleaning and/or sanitizing liquid that is fed into the freezingcylinder 17 through the normal product mix inlet 26 c, fills thefreezing cylinder, and with normal operation of the dasher or beater110, (which shall be described more completely hereinafter) with therefrigeration cycle cut off, and the product dispensing valve 60 open,the freezing cylinder 17, the door assembly 80 and dispensing valve 60are all exposed to the cleaning and/or sanitizing liquid. As may be seenhereinafter, the door and valve construction are such as to facilitateproper cleaning action without undue operator attention.

FIG. 10 illustrates the manner in which the motor shaft 111 connectsthrough an end cap 17 c of the freezing cylinder 17. Because thefreezing cylinder, when in operation, is under pressure due to theproduct mix being agitated by the dasher or beater 110, it is desirablethat product be inhibited from entry into and along the shaft 111 andinto the motor 25, through the shaft mounting housing or frame 141,which supports the motor 25 and the freezing cylinder 17 at one end bythe end cap 17 c. To this end, the shaft 111 is provided with a pair oflongitudinally spaced apart, cylindrical, circumferentially extending ofthe shaft 111, flexible-wear resistant seals, 142, 143 respectively. Asnoted, the seals 142 and 143 are substantially wedge shaped in crosssection, with their heal portions 144 adapted for receipt intocircumferentially extending slots 145 in the bore 146 of the end cap 17c. As shown in FIG. 13B, each seal is angled so as to terminate at itsforward end or bearing end 147 against the shaft 111, so as to form aknife-edge-like seal against the shaft.

Inasmuch as the seals 142 and 143 are composed of a flexible material,wearing of the bearing ends 147 against the shaft, and due to shaftrotation, is self compensating. In practice, the seals are preferablycomposed of a material that is food grade, i.e., will not deteriorateinto the product and contaminate the same, are easily cleaned and havegood wear characteristics. One such seal material and seal is apolyurethane of a food grade type, H-Ecopur manufactured by Eco SealTech, Inc. 26820 Fargo Ave., Cleveland Ohio.

In the event that some leakage or seepage does occur through the seal142 into the space intermediate seals 142 and 143, means are provided toclean the seals and the space to prevent bacteriological materialbuildup and to prevent a consequent contamination source. Referring nowto FIGS. 5 and 10, when the valve 33 is in the second position such thatthe air supply is interrupted between the needle valve 32 and the threeway dump valve 33, cleaning and/or sanitizing liquid is supplied to thefreezing cylinder 17 via check valve 48, while the two way valve 133 isbeing supplied with cleaning and/or sanitizing liquid via line 133 a.When the valve 133 is open, such as shown in FIG. 5, the cleaning and/orsanitizing liquid is supplied through seal purging opening 148 a vialine 133 b extending from valve 133. The liquid, of course, afterpurging the seals 142 and 143 and the space therebetween, may bedisposed of through discharge opening 148 b and drain line 149.

It should be recognized, of course, that the end cap 17 c of thefreezing cylinder 17 may be made integral with the housing or frame 141.In that instance, the cleaning and/or sanitizing inlet and outletapertures 148 a and 148 b would reside in the frame or housing. As shallbe described hereinafter, the freezing cylinder door assembly 80 andproduct valve assembly 60 are also constructed in a manner to allow forcleaning with cleaning of the freezing cylinder and the remainder of thesystem, without disassembly of the machine.

PRODUCT MIX LEVEL SENSING

The simple metering assembly provided above and as described and shownin the drawings also provides a method for sensing the level of productmix in the pressurized mix container 43. Whether the product mix withinthe container 43 is liquid in the container or in a mix bag or the likesuch as shown at 44 in FIG. 4, the method of determining the amount ofmix in the container is determined by dumping or opening the three waydump valve 27 for a predetermined period of time, while monitoring thetime and measuring, as through a suitable signal line to the control 55,the change in pressure for that period of time. The change in pressureis inversely related to the quantity of mix remaining in the tank. Analternate method is to open the three way dump valve 27 until thepressure drops to a predetermined level and measuring the time it takesto drop some predetermined pressure. In this case, the amount of time isinversely related to the quantity of mix remaining in the tank. Thisgives a good indication, by practicing this method at convenient times,to determine the level of mix remaining in the pressurized mix container43 so that the operator may replace or add to the mix when needed.

However, while this level sensing method can be quite accurate, it doesnot indicate exactly when the tank is empty. Another method is thusemployed to indicate to the operator that the mix has been depleted fromthe pressurized mix container.

To this end, an instrument, such as a probe and the like 51 is suppliedto provide a feedback to the controls/control system 55 as by signalline 51 a and give a positive indication to the operator that the mixhas been depleted. As an example only, a thermister probe whichprotrudes into the barrel 26 may be employed. By energizing a thermisterin the mix flowing in the barrel with a small electrical current, theresistance of the thermister causes heating. When mix is present in thebarrel, and surrounds the probe or thermister tip, the thermalconductivity of the liquid mix rapidly dissipates the heating of thethermister. However, when the mix is depleted, the thermal conductivitysurrounding the probe is reduced and the thermister heats up. This risein temperature can be electrically sensed by the controls/control system55 since the resistance of the thermister is lowered with risingtemperature. In this manner, the instrument detects the presence orabsence of the liquid mix entering through the barrel 26.

DOOR AND PRODUCT DISPENSER

The door assembly 80 along with the product dispensing valve assembly60, serves to lock and seal the one end 17 a of the freezing cylinder17. The door assembly 80, is shown in FIGS. 6-9, and includes a door 85and cover 81. The door 85 is adapted to secure, upon accurate alignmentagainst a radially projecting rim 17 b of the freezing cylinder 17, withthe cover 81 bearing against the door 85 and locked in place as by aring 82, which may form part of the cover, plus an interlock provided bythe product dispensing assembly 60. To this end, alignment of the door85 onto the rim 17 b of the freezing cylinder 17 is ensured, asillustrated in FIGS. 6 and 9, by projections or tabs 86 a, 86 b whichproject co-axially from the door 85 for mating insertion intoreceptacles or notches 87 a, 87 b in the rim 17 b. As shown best inFIGS. 6 and 7, the tabs 86 a and 86 b as well as their associatedreceptacles or notches 87 a, 87 b are of different sizes to inhibitplacement of the door in an upside down position. Of course, theprojections or tabs 86 a, 86 b may be located on the rim and the notchesor receptacles 87 a, 87 b may be located on the door, for a simplereversal of parts.

The ring 82 also includes radially extending slots or recesses 88 tograsp (see FIG. 9) and engage in locking fashion radially extendingbayonet type locking tabs 89 on the rim 17 b. Moreover, because of theconstruction of the cover 81, spaced from the door 85, a space 81 a isformed intermediate the door and cover to form an insulator. Inasmuch asthe various parts may be composed of a plastic, e.g., thin wall moldedplastic parts, not requiring any secondary machining operation, thedouble walls and spaced apart walls of the cover and the door inhibitthe formation of condensation.

In order to ensure a tight seal of the door 85 against the rim 17 b ofthe freezing cylinder 17, and as shown best in FIG. 9, the door isprovided with an annular projection 91 which is aligned with an annularreceptacle 92 in the rim 17 b of the freezing cylinder 17. A Z-shaped incross section, seal 93, having radially depending legs 93 a, 93 b, isengageable with the rim 17 b. To this end the leg 93 b is fittable inthe receptacle 92 to receive the annular projection 91 and to provide,when seated, a seal, in the illustrated instance a tertiary seal, i.e.,an axial seal. The primary or initial seal is another axial seal formedby the leg 93 a abutting a radial shoulder 91 a underlying the annularprojection 91. The secondary seal is a radial seal formed between theaxial inner surface of the annular projection 91 and the portion 93 c ofthe Z-shaped seal 93.

In practice, if the ring 82 is formed (molded) as part of the cover 81,the cover is rotated to allow proper mating of the cover to the lockingtabs 89 on the rim 17 b of the freezing cylinder, and then rotated inthe opposite direction to effect a mating of the cover to the freezingcylinder. As illustrated best in FIG. 9 when the recesses 88 in the ring82 are in engagement with the tabs 89 (FIG. 9), the cover pressesagainst the door causing firm sealing and engagement of the annularprojection 91 into the cup shaped cross sectional seal 93 forming adouble axial seal and a radial seal therebetween. Once again, it isrecognized that the annular projection may be placed on the rim and thereceptacle and seal on the door in a simple reversal of parts.

In order to lock the cover to the door and the rim 17 b of the freezingcylinder 17, and as best shown in the exploded view of FIGS. 2, 6, 7 and9, the product dispensing or valve assembly 60, when placed within thedoor assembly 85, locks the body to the cover preventing inadvertentdoor opening or separation of the door from the freezing cylinder.

To this end, the valve assembly 60 includes a generally cylindricalreceptacle member 62 which is fitted through a keyed aperture 82 b inthe cover 81. As shown, the receptacle 62 has a depending skirt portion63 which is twist locked as by the radially extending tabs orprojections 62 a into recesses 83 a in the bored hole 83 in the door 85.(see FIG. 9). A second receptacle 63 a is placed in the bored hole 83and twist locked as at 63 b into position abutting the terminal end ofthe skirt 63 of the first receptacle 62. The second receptacle 63 a alsoincludes a flared depending annular skirt 64 including an annular cavity65 therein. A piston 67 has a head end assembly 66 formed at the end ofa shaft 67 a. As shown, the head end assembly includes a diaphragmportion 68 which circumscribes the skirt 64 of the second receptacle 63a causing the diaphragm to be captured between the wall of the bore 83and the skirt 64 of the second receptacle 63 a. As the pistonreciprocates due to actuation of the handle 61, affecting elevation ofthe shaft 67 about a pivot pin 61 a, the rolling diaphragm 68 movesupwardly into the cavity 65 elevating the piston and head end assemblyin a manner hereinafter described, and inhibiting the flow of productinto the bore 83.

As illustrated, softserve product may pass from the freezing cylinder 17into a passage way 69. As shown in FIG. 9, the valve dispensing head endassembly 66 intercepts the passageway 69 and seals off a product outlet70 in the door. As shown in FIG. 9, the sealing end or piston head endassembly 66 forms an interference type fit against a beveled edge orseat 66 a formed in the door adjacent the product outlet port or exit70. As the shaft 67 a is raised by rotation of the handle 61 about thepivot pin 61 a, a biasing spring 71 causes, upon release of the handle61 reseating of the valve head assembly 66 against the seat 66 a sealingoff the passageway 69 and the outlet 70.

To facilitate the opening of the valve 60, an actuator such as asolenoid 59 may be employed to permit the opening of the valve undercontrol of the controls/control system 55. At this juncture in thedescription, it should be noted that the product exodus from the drawvalve is such that product contamination of the valve, its actuator andoperating mechanism is prevented because of the sealing action of therolling diaphragm, facilitating the clean-in-place operation.

THE BEATER (DASHER) ASSEMBLY

Referring first to FIGS. 2, 6 and 10-13, the beater 110 comprises, in afirst embodiment, a foraminous tube 112, which because of itsconstruction is light, highly durable and possesses great torsionalstrength. A front, product pushing helical member or element, in theillustrated instance an insert 114 of the beater is dimensioned forinsertion into one open end 113 of the tube 112, and includes oppositelysituated, radially projecting or protruding keys 116 thereon forregistration in slots or key ways 115 in the end 113 of the tube 112. Asshown, the insert 14 includes a helix shaped front end 118 to facilitatethe movement of the softserve product into the passage way 69 and outthe outlet 70 of the door assembly. A plurality of blade scrapers 120,122 are coupled to the exterior of the tube 112 in any convenientmanner, in the illustrated instance by mating holes 121 and studs 123.If desired, the blade scrapers may be attached to the cylinder 112 by akey and notch arrangement which allows for engagement of each bladescraper to the cylinder 112. Alternatively, the blade scrapers may be ofa snap-in design where no fasteners are required. This is acceptable (asin the arrangement shown in FIG. 6 where a simple stud and mating holeprovide alignment of the blade scraper with the cylinder 112). Thereason for this is that the blade scrapers, 120, 122, when in positionwith the cylinder 112 mounted in the freezing cylinder 117, cause theblades to press against the interior wall of the freezing cylinder 117in scraping engagement therewith. In order that wear of the blades iscompensated, and depending upon the material of construction, the bladescrapers or the blades thereon may be biased radially outwardly as bysprings on the studs, or a leaf spring construction intermediate thecylinder 112 and the interior of the blade scrapers 120, 122 or even bymounting the blades as separate parts on the scrapers.

As shown best in FIG. 11, the blades on the blade scrapers form, when inposition, a helix which is dimensioned for scraping engagement with theinterior of the freezing cylinder for whisking softserve product fromthe cylinder as it rotates therein while simultaneously urging thesoftserve product towards the door or front end of the freezingcylinder. The driving portion of the beater 10 comprises a hub 112 awith a keyway type connection for coupling to the shaft 111 and fittableinto the opposite end 113 a of the foraminous tube or cylinder 112 fromthe helical product pusher portion 114. (See FIGS. 10 and 13A)

By constructing the blade scrapers as well as the helical beaterinserted in one end of the foraminous cylinder, of plastic, an improvedbeater or dasher assembly is provided.

To improve the mixing and blending of the product as it is frozen andwith rotation of the dasher or beater 110, and as best shown in FIGS. 2,6 and 12, a baffle rod 124 is mounted interiorly of the foraminouscylinder 112. To this end, the baffle rod 124 is fixed against rotationby a key 125 which coacts and mates with a receptacle 95 in the doorassembly 80. (See FIGS. 6 and 9). The baffle rod 124 is eccentric withrespect to the axis of rotation of the beater 110, the beater rotatingconcentrically of the axis of the freezing cylinder 117. By making thebaffle rod 124 eccentric (or alternatively mounting it eccentrically ofthe foraminous cylinder 112), as the cylinder rotates, the baffle rodserves to fold and facilitate mixing of the softserve product as theproduct is moved within the freezing cylinder. Moreover, by making thebaffle rod relatively large in diameter so as to consume more internalvolume of the forminous cylinder 112, product waste is minimized whenthe machine usage is complete during the business day.

As shown best in FIG. 10, the opposite end of the baffle rod terminatesin a protrusion 126 which abuts the end of the rotating shaft 111.Additionally, a flow interrupter, in the illustrated instance comprisinga pair of spaced apart disks 127, 129 are mounted on the baffle rod 124,each of the disks having a scalloped peripheral edge portion 127 a, 129a and a circumferentially extending smooth portion 127 b, 129 brespectively. The smooth portions 127 b and 129 b ride against theinternal surface of the foraminous cylinder 112, maintaining theposition of the baffle rod in the cylinder. The scalloped peripheraledge portions 127 a and 129 a, because of the flow of the mix throughand around the holes in the foraminous cylinder 112 as it rotates,increases the mixing action of the product mix. As may easily beenvisioned, the mix is forced forward towards the door assembly 80 bythe helical action of the scraper blades and the pushing action of thehelical portion 114. Subsequent mixing action occurs because the productmix tends to flow through the center of the foraminous cylinder 112,around the baffle rod and past the disks 127 and 129. This insuresuniformity of the mix during the freezing cycle.

An alternative embodiment of the beater or dasher 610 is shown in FIG.14A. In this construction, except for additional scraper blades 620,622, a less expensive but durable construction of a beater is shown. Inthe present instance the foraminous tube 612, which because of itsconstruction is light, highly durable and possesses great torsionalstrength is constructed of a molded or cast stainless steel. Similar tothe embodiment of the dasher or beater 110 illustrated in FIG. 10, afront, product pushing helical insert member or element 614 isdimensioned for insertion into one open end 613 of the tube 612, andincludes oppositely situated, radially projecting or protruding keys 616thereon for registration in slots or key ways 615 in the end 613 of thetube 612. As before, the insert 614 includes a helix shaped front end618 to facilitate the movement of the softserve product into the passageway 69 and out the outlet 70 of the door assembly (see FIG. 9). Indistinction to the construction of the beater 110 shown in FIG. 10, thecurved elements 635 form a broken helix along the periphery of the tube612, but preferably do not contact the inner surface of the freezingcylinder 17 but serve, during rotation of the tube or cylinder 612,merely to facilitate mixing and movement of the freezing product mixtowards the helical insert member or element 614 and out of the machine1 during product draw. However, the scraper blades 620, 622 are mounted180° apart, co-axially on the periphery of the tube 612. In a manner setforth below, the blades are mounted so that rotation of the tube orcylinder 612 in the direction of the arrow 630, causes product mix togather beneath the blade, forcing it to rotate towards the interior ofthe freezing cylinder 17 and effect a whisking action of the freezingproduct mix material from the interior surface of the freezing cylinder.Additionally, the blades 620 and 622 have axial or longitudinal extentssufficient to whisk the desired working surface of the interior of thefreezing cylinder 17.

A single scraper blade 620 is shown in FIG. 14B, and includes aplurality of tabs 624, 626, and 628. The tabs, as shown, are offset fromthe blade portion 621 of the scraper blade so as to permit easyplacement into slots 625 in the surface of the tube 612, and so thatwhen in position within the freezing cylinder, are allowed some freedomof rotation to accommodate product mix forcing the scraper bladeoutwardly against the freezing cylinder as shown best in FIG. 14C by thearrow 636. Moreover, by dimensioning at least two of the tabsdifferently and insuring that the mating apertures are dimensioned toonly receive the mating tabs in one orientation of the scraper blade onthe foraminous cylinder 612, it is impossible to fit the blades in theimproper location. This difference in dimensions of the tabs 624, 626and 628 is evident in FIG. 14B.

As before, the baffle rod 124 may be positioned interiorly of the tube612 and operate in the same manner as heretofore described.

MODES OF OPERATION (STATE MACHINES & SOFTWARE) Overview

In principle, the software for operation of the machine, via thecontrols/control system 55, may be structured around a time slicingkernel. However, the system should not be entirely a deterministic multitasking system. Some functions of necessity are preferably operatedinterrupt driven, while others should be operated without interruption.While at first blush this would seem to complicate system design andoperation, this approach to system design permits a building blockapproach and allows for subsequent alteration in the system with newfeatures, when such is desired.

With the forgoing in mind, there are seven fundamental modes ofoperation of the softserve machine 1, all of which may be thought of asseparate “state” machines. (It should be noted that a separate, or8^(th) mode called “standby” is discussed briefly with regard to FIG.15, but this mode is generally not considered a separate one, althoughit is treated as such herein, and discussed below.) FIG. 15 illustratesthe basic state machine diagramming the general software structure andrequirements for the fundamental mode of operation of the machine 1. Asshown in FIG. 15, as that state machine diagram discloses, the machine 1starts up by powering it up as at 200 (the control for such being, forexample, located on the control and display panel 150, shown in FIGS. 1and 2.). The machine, under command of the controls/control system 55,then goes into an “Off” mode in which the machine is in an idle state,but ready for operation and waiting for a further command, or goes intoa “standby” mode, if such is commanded.

The “standby” mode is similar to the auto mode (described below) exceptthat the product is held between the frozen condition and 40° F., (i.e.,a cold liquid). This mode is employed during times when the product isthought not to be needed instantly, and allows for an increase in timebetween refrigeration cycles as well as reduced utilization of thedasher/beater. This mode is useful at times when it is doubtful thatproduct will be demanded.

As shown by the state diagram in FIG. 15, there are several commands foroperating the machine in a number of different modes that may be given.For example, the machine may be placed in a clean-in-place mode as at240, or it may go into a beater mode in which the beater 110 is causedto rotate; or it can go into the auto mode which commences charging orpriming the freezing cylinder 17 with mix from the mix cabinet 40 andcontainer 43 as indicated by the block 260. When the machine enters thebeater mode as at 220, it is really in the powered up mode, the beater110 is turned on as by the motor 25, the air compressor 25 a may bestarted and the air pressure may be brought up to a normal operatingpressure so as to pressurize the mix container 43. While such pressureis dependent upon multiple system parameters, an air pressure ofapproximately 5 psi has been found to work well.

Assuming that the machine has entered into the prime mode 260, and thebarrel or freezing cylinder 17 was initially empty and is in the processof being charged with a liquid mix product, once the mix is at somepredetermined minimum level, the initial freeze down mode as at 262 maycommence. Once the product has been frozen and is ready for serving, themachine state is transferred to the product ready mode 264. In thismode, several actions may occur. For example, a product draw may takeplace (i.e., the product handle 61 dispenses through the productdispensing valve 60, semi frozen/softserve product). Once a draw occursor the product starts getting warm, or a selected amount of timeelapses, the machine state switches to a product maintenance mode as at266. In this mode the product is maintained at a desired quality levelboth as to temperature, mixture of air therein, etc.

When the product has been maintained at some predetermined desiredlevel, the machine state switches back to the product ready mode 264 andcycling continues. If no draw has taken place, and a predeterminedperiod of time has elapsed, e.g., 15-20 minutes, (which may be settableas desired), the product needs to be re-frozen and re-blended so thecontrol 55, under software direction, will switch the machine back tothe product maintenance mode 266, correct the deficiencies in theproduct quality, and bring the machine back to the product ready mode264. In the event that the product ever gets too warm in the freezingcylinder, for example if the machine happens to be positioned adjacent adeep fat flyer at 140 degrees and time doesn't elapse, a sensor in thefreezing cylinder may effect a shift of the machine to the productmaintenance mode 266 via the control 55.

Power-up Mode

Turning now to FIG. 16, a state-diagram of the power-up mode of thesoftserve machine 1 is illustrated therein. In this mode, the control 55first checks itself with a POST (Power On Self Test) 201 to insure thatthe system is present and has the ability to function. This test isconducted only at power up. Other tests, such as BIT (Built In Test) aretests that may be conducted not only at power up, but periodicallyduring operation. Many of these tests are similar or the same as thoseconducted during start up and operation of a personal computer. Some ofthe tests would include short and open tests on temperature sensors;peripheral inquiry via the RS-485 bus (which bus shall be describedrelative to FIG. 23); memory tests, both RAM & ROM; indicatorbulbs/LED's; alarm & other indicators, and interlocks, (e.g., theinterlock on the door 40 a of the refrigerated auxiliary mix storagecabinet 40).

As is conventional, the parameters of the operation may be retrievedfrom data contained in non-volatile memory and employed in softwarecontained in the control 55. For example, the software may analyze thetemperatures within the machine and determine what state the system wasin when power was removed, and allow, if conditions permit, forautomatic restart. In the event the machine 1 is empty, i.e., nopressure sensed in the mix feed to the freezing cylinder or barrel 17,then no recovery is necessary and the machine awaits the command fromthe operator to press the “Auto Button”. (As shown in FIG. 16, several“Buttons” are designated, e.g., “Auto Button”, “Beater Button”, “StandBy Button” and “CIP Button” (Clean-In-Place initialization). Each ofthese buttons may be placed, for example, on the control and displaypanel 150, illustrated in FIGS. 1 and 2. If the machine is not empty,that is a pressure greater than 0 psi is detected, and the mix cabinet40 temperature is above a predetermined temperature, e.g., 45 degreesF., an alarm/indicator/light, etc. may be activated on the panel 150 towarn the operator that the product has become too warm to be re-frozensafely. To start operation, the operator may then use the “Auto Button”.The indicators for “pressure in the system” or “over temperature” maytake any convenient form that will alert the operator that the system ispressurized or the product mix exceeds maximum allowable temperature forre-freezing. If the machine is not empty (i.e., pressure greater than 0)and the product is within normal temperature range (e.g., 20 degrees F.or less), then the machine will return to its product ready mode 264.Alternatively, if the machine is not empty (pressure>0 p.s.i.) and theproduct mix temperature in the freezing cylinder is within safe limits(e.g., greater than 20 degrees but less than 40 degrees F.), thesoftware forces the machine into the product maintenance mode 266 inwhich an attempt is made to re-freeze the product and then return themachine to the product ready mode 264. The clean-in-place mode 240 isalso, as is explained above, is entered into from the off or idle mode204. Its operation will more fully be explained with regard to FIG. 21,hereinafter.

Prime Mode

Referring now to FIG. 17, a diagrammatic view of the prime mode isillustrated. During the prime mode, several activities under softwarecontrol occur simultaneously. First and foremost, air pressure serves toprime the freezing cylinder with the raw product mix. Simultaneously,the control 55 monitors the system to insure that all other dependentsystems are operating properly. For example, that pressure in thefreezing mixture and the freezing cylinder is rising; that thetemperature in the freezing cylinder 17 is decreasing; that the mixlevel in the freeze cabinet is within operating limits; that enunciatorsor indicators are updated; that all operator inputs are read; and thatall safety features are operating safely within design limits. As theair pressure is monitored, when the pressure reaches some predeterminedlevel, for example, 8 p.s.i, as shown in block 261 a, it will beunderstood that the priming operation is complete and the prime mode isexited as at block 261 b. Thereafter the initial freeze down mode iscompleted.

Freeze Down Mode

Turning once again to the drawings, and especially FIG. 18, FIG. 18 is astate diagram illustrating the initial freeze down mode in which the rawproduct is frozen for the first time. Assuming that the system is primedwith product, the initial freeze down mode is then commenced, as shownat block 262 a. The beater system 220 is activated and the beater orforaminous cylinder or tube 112 is rotated. When the initial freeze downis completed, it is desirable that mix cabinet 40 starts to cool thesupply of product mix in the mix storage cabinet 40. In this connection,and referring to FIG. 3, the solenoid valve 21 is opened and mix cabinetcooling is commenced, as depicted in block 262 b. The refrigerationcompressor 18 is then energized to start the refrigeration system. Thisactivity is depicted at block 262 c. The control algorithm for therefrigeration system is such as to maintain the optimum evaporatorpressure, given the current operating environment. In the interim, thecontrols/control system 55 are monitoring the system, for example, alltemperatures, system pressures, current and voltages of the motors etc.It should be recognized that each of the control lines, although beingshown as single lines, may in fact included multiple electrical leads toand from the controls/control system 55. For example, through controlline 25 b, current being drawn by the motor 25 may be measured todetermine the amount of torque transmitted to the beater as it rotatesthrough increased resistance of product mix in the freezing cylinder 17.When some predetermined percentage of the torque required to effectrotation of the beater when the freeze down is completed, and thatpercentage is measured or calculated, the refrigeration compressor 18 isturned off, such as shown in block 262 d. This is done to prevent overfreezing of the product in the freeze cylinder 17, and allow residualcooling to finish the freeze down. When the measured or calculatedtorque reaches the amount of torque required to effect rotation of thebeater when freeze down is completed, the beater system is turned off,such as shown at block 262 e. The softserve product is then ready andthe initial freeze down mode is exited, as shown at block 262 f. It isrecognized that the means for determining the finishing point of thesoftserve product may take any number of forms, from temperature toactual consistency of the product, on a test basis. However, bymeasuring torque, a simple and repetitive mode of operation may beconsistently applied.

In the event a product draw is attempted before the product reaches apredetermined frozen consistency, an aural/visual indication may beprovided from/on the control and display panel 150. Moreover, if themeasured air pressure drops below some predetermined number (e.g., 5psi) due to the draw down, the coolant compressor 18 may be shut down totemporarily cease the freezing activity, and may be turned on again whenthe air pressure reaches, for example, 8 psi.

There are other conditions which should produce warnings or shut thesystem down. For example, if liquid refrigerant is fed back to therefrigeration compressor 18, to prevent refrigeration system damage, thesystem should be shut down. Other conditions which should be detectedand the initial freeze down mode exited, are if the product lowtemperature trip point is reached, or if the refrigeration compressor ison for greater than some definitive time, e.g., 10 minutes with the drawis handle 61 closed; or if the beater is unable to reach torque aftersome predetermined period of time, e.g., 12 minutes.

Product Ready Mode

The product ready mode is depicted in FIG. 19. As has been explainedheretofore, once the product has been frozen and is ready for serving,the machine state leaves the initial freeze down mode, as discussedrelative to FIG. 18, and the machine state is transferred to the productready mode 264 (FIG. 15), as by a signal indicating that the product isready, as at product ready entry block 264 a. In this mode the productis at the required quality level. The system uses passive cooling duringthis time to keep the product at this level for as long as possible. Inthis mode, several actions may occur. In the first instance, the control55 must continuously monitor the system status, such as shown at block270. (The looping line 271 is to indicate the monitoring or loopingaction of the software controlled control 55). For example, a productdraw or draw down may be anticipated as by a draw down proximitydetector which senses the approach of an operators hand to the draw downhandle 61. Upon sensing the approach of a hand to the product draw downhandle 61, the beater motor 25 may be activated as at block 220. Oncethe draw switch or solenoid 59 is energized, the product ready modeexits to the draw mode 272, and the product handle 61 causes semifrozen/softserve product to be dispensed through the product dispensingvalve 60. Once a draw occurs or the product starts getting warm, or aselected amount of time elapses, the machine state switches to a productmaintenance mode as at 266 and the cabinet temperature, for the productmix, at some point requires active cooling. In this mode the product ismaintained at a desired quality level both as to temperature, mixture ofair therein, etc.

When the product has been maintained at some predetermined desiredlevel, the machine state switches back to the product ready mode 264 asat 264 a and cycling continues.

Product Maintenance Mode

In order that the quality of the product is maintained, it is necessarythat the machine enter into a product maintenance mode 266 (see FIG. 15)so that if the product temperature, monitored by the control 55, exceedsa predetermined limit, or the product has been allowed to sit in thebarrel too long and needs to be refrozen and air reincorporated, themachine, under control in this mode, accomplishes all of these things bymaintaining the product at a desired quality level both as totemperature, mixture of air therein, etc. When the product has beenmaintained at some predetermined desired level, the machine stateswitches back to the product ready mode 264 and cycling continues.

To this end and referring now to FIG. 20, product maintenance entry 266a is a block representation of the entrance into the maintenance mode266. For example, suppose the product temperature in the freezingcylinder 17 has exceeded some predetermined limit, as determined bydiffering stored setpoints and control variables in the control 55.Under these circumstances, the software will load the variables, as at267, for commencing the restoration of the product to the desiredquality level. In this connection, the beater system 220 is activatedand the beater or foraminous cylinder or tube 112 is rotated. It isdesirable that mix cabinet 40 starts to cool the supply of product mixin the mix storage cabinet 40. As discussed heretofore, and referring toFIG. 3, the solenoid valve 21 is opened and mix cabinet cooling iscommenced, as depicted in block 262 b (FIG. 18). The refrigerationcompressor 18 is then energized to start the refrigeration system. Thisactivity is depicted at block 262 c. In the interim, thecontrols/control system 55 monitor the system, for example, alltemperatures, system pressures, current and voltages of the motors, etc.As described heretofore with respect to the freeze down mode depicted inFIG. 18, the refrigeration compressor 18 is run until a predeterminedpercentage of the torque required to effect rotation of the beater whenthe freezing of the product is completed. The refrigeration compressor18 is then turned off, such as shown in block 262 d. Residual cooling isthen permitted to complete the freeze down. When the measured orcalculated torque reaches the amount of torque required to rotate thebeater when freeze down is completed, i.e., beater target torque isreached, as at 262 e, the beater system in turned off. The productmaintenance mode may then be exited as shown in product maintenance exit290 when the product quality setpoints are reached.

Product maintenance also occurs upon product draw, when the variablesand setpoints for product draw for the software take place as at block268, or; if too much time has elapsed as at block 269, or the controlindicates (through the software) that the variables for the mix cabinet40 must be loaded to effect active cooling thereof In each of thoseevents, the beater system is turned on as at 220, the refrigerationcompressor 18 is turned on (block 262 c) and later turned off (block 262d) when some percentage of beater final torque is reached, and thenfinally, the beater system if turned off as at 262 e. Once again, theproduct maintenance mode may then be exited as shown in productmaintenance exit 290, when the product quality setpoints are reached,and the product ready mode 264 may be entered.

Clean-in-place Mode (CIP)

As has been explained heretofore, it is highly desirable that the amountof disassembly of the machine in order to clean it, be minimized. Asdiscussed in the section of this specification entitled“Clean-In-Place”, the machine 1 is equipped with clean-in-placeapparatus which allows for cleaning of the machine with minimal humanattention. To refresh the readers recollection, and referring first toFIG. 5, when it is desirable or necessary to clean the productcontaining portions of the machine 1, the pressurized mix container maybe provided with a quantity of cleaning and/or sanitizing liquid. Themix container is pressurized and the cleaning and/or sanitizing liquidis ejected through line 46 and therefore ultimately to the freezingcylinder 17. Pressurization of the mix container 43 occurs because theoperation of the three-way dump valve 27 will allow application of airpressure from the air compressor 25 a, through the line 29 a, and ofcourse into the pressurized mix container 43. The operation of thesolenoid operated three way dump valve 33, into the position illustratedin FIG. 5, turns that valve into a wash valve which cuts off the air tothe line 29 c and check valve 34. By its position, it now flushes orwashes with cleaning and/or sanitizing liquid, the air check valve 34and the mix check valve 48 merely by forcing cleaning and/or sanitizingsolution through line 46, past tee 47, through lines 46 a, 47 a and thevalve 33, into the barrel 26 and then into the freezing cylinder 17through the product mix inlet 26 c.

As may be seen from the forgoing description, the cleaning and/orsanitizing liquid enables easy flushing of the lines and valves normallyexposed to the product mix.

The cleaning and/or sanitizing liquid that is fed into the freezingcylinder 17 through the normal product mix inlet 26 c, fills thefreezing cylinder, and with normal operation of the dasher or beater 110causing agitation of the cleaning and/or sanitizing fluid within thecylinder 17, with the refrigeration cycle cut off, effects purging ofthe freezing cylinder. When the product dispensing valve 60 opens, thefreezing cylinder 17, the door assembly 80 and dispensing valve 60 areall exposed to a flushing action because of the flow of the cleaningand/or sanitizing liquid therethrough.

The sequence of operations and the mode of operation is depicted in FIG.21. Turning now to that drawing figure, the CIP mode is entered into bythe operator command as at block CIP MODE ENTRY 241. This can beaccomplished by a simple switch or control on the control and displaypanel 150. Upon entry into the CIP mode 240, the air compressor outletis adjusted to some finite level, e.g., 5 psi, such as depicted at block242 in FIG. 21. This effects pressurization of the mix container 43.Simultaneously, the dump valve 33 and the valve 133 is moved to theposition illustrated in FIG. 5, and depicted by the block 243 (set washvalve to on) in FIG. 21, and those valves now serve as a wash valve forpermitting cleaning and/or sanitizing fluid into both the freezingcylinder 17 and the into the seal inlet 148 a (for cleaning and/orsanitizing the space intermediate the shaft seals as well as the sealsthemselves). The beater system is then turned on as shown in block 220.The system is then preferably placed in a hold or delayed state 244 forsome predetermined period of time, depending upon the barrel 26 andfreezing cylinder volume as well as cleaning and/or sanitizing liquidflow, for example for a few minutes, while the barrel 26 and freezingcylinder 17 are filled with the hot cleaning and/or sanitizing liquid.

In order that the lines, barrel 26, freezing cylinder 17, productdispensing valve assembly 60 may be properly purged of any food productmix, the beater 110 is kept in motion. Moreover, a cycling action isthen instigated by the software to repetitively open the productdispensing valve 60, i.e., under control of the solenoid 59 andoperation against the handle 61 of the valve 60. Return of the handle 61to its closed position is effected by the return spring 71. This permitshot cleaning and/or sanitizing liquid to flow through the system and bedispensed out of the product outlet 70. (See FIG. 9). By cycling(opening and closing of the product dispensing valve 60), forpredetermined periods of time, the entire system may be purged andcleansed. Moreover, by cycling the system for differing time periods,differing and varying pressurizations, rarefactions, surging and purgingactions (sloshing) are set up within the system which tend to dislodgeany stubborn or difficult to dislodge food particles. While these timeperiods may be varied, and their number altered dependent uponexperience with different products, the cleansing of the system isassured by the cyclical action. This action is best illustrated in FIG.21 as in blocks 245, where the product draw valve is opened for anexemplary time period of 1 minute, closed for 1 minute as in block 245a, and the action is repeated three times as shown in block 245 b. Thissequence of repetitive cycling actions for exemplary differing timedurations or periods is depicted in blocks 245 c-245 g. It should benoted that these time periods and sequencing actions are by exampleonly, and proper and complete cleansing of the machine 1 product sideare dependent upon cleaning and/or sanitizing liquid composition,temperature, volume and pressure as well as the retentiveness, abilityto break down into its constituent parts, the food product itself.

The product draw valve 60 may then be finally closed as shown at block246, the beater system 110 turned off as at block 247, the air pressureturned off and pressure dumped as at block 248 and the clean-in-placemode exited as at 249.

CONTROL 55 OR CONTROL SYSTEM 550

The control or control system 55 is the hardware system that operates inconjunction with and under control of the software to effect the modesof operation described in the section of this specification entitled“MODES OF OPERATION (State Machines & Software)”.

Turning first to FIG. 22, the control system 550 comprises, at afundamental level, a main CPU and operator interface display board ormain control board 555, and one power I/O board 570. These twocomponents are coupled by an RS-485 serial data bus 560. The power I/Ofunctions as a slave to the main CPU. When the system is expanded, forexample into a dual freezing cylinder machine, a second power I/O boardmay be added such as shown in dotted lines at 571. Of course whenadditional options are desired for the system, such as shown in thedotted line block Optional Board(s) 572, additional slave boards may beinstalled on the RS-485 data bus to ascribe specialized I/O required fora desired particular function. Other boards coupled to the RS-485 serialData bus 560 include a data logger and communications boards 580, aclean-in-place (CIP) control board 590 and a refrigerated control board600 for the mix cabinet 43.

The main control board 555 is illustrated in FIG. 23 and is constructedaround a controller, in the illustrated instance a micro-controller/CPU556 such as a Hitachi H8 micro-controller. The advantage of thisparticular micro-controller is that it contains Flash ROM for theapplication program, system RAM (random access memory), analog todigital (A/D) converter, digital I/O ports and a built in communicationssystem. However, other processors and/or micro-processors may beemployed with suitable peripheral devices and architecture to accomplishthe necessary functions. In the illustrated instance, external to themicro-controller 556 is an EEPROM 556 a which is used to storecalibration, setup, configuration and fault data. Externally of the A/Dconverter is an analog multiplexer 557 and analog and digital signalconditioning circuits 558 a, 558 b respectively, that interface variousanalog logic sensors (pressure, temperature with associatedpotentiometers) and digital sensors (e.g., positioning sensors) to themicro-controller 556. The communications multiplexer 557 includessuitable driver circuits that allow the system to interface with variousstandard communications protocols, e.g., the RS-485 transmitter andreceiver 557 a for internal CPU board control of the bus 560; an RS-232transmitter and receiver 557 b for external communications anddiagnostics and, if desired, an infra red (IR) transmitter and receiver557 c which permits wireless, short range, infra-red lightcommunication, also for such things as data and diagnostics.

The operator interface 559 is machine dependent and my be visuallyinterfaced to the operator as at the control and display panel 150 (seeFIGS. 1 and 2). The interface may provide the operator with I/O pushbuttons, enunciators (lighted icons), digital displays, LED indicatorsand the like. As shown, the CPU board 555 may be provided with its ownlocal power and DC voltage regulation as at 554, and also provided witha “fail-safe” programming connector 553 which allows updating theapplication within the micro-controller 556. It should be recognized,however, that in normal operation, updating may occur through and by wayof the RS-232 transmitter and receiver 557 b and/or the IR transmitterand receiver 557 c.

The power I/O board 570 may be a plug in or insertable daughter boardfor the main control board 555, but is preferably of a distributedcontrol architecture where the processors are situated close to theiractuators or sensors which they control. Turning now to FIG. 24, at theheart of the power I/O board 570 is a micro controller 573. While themicro-controller may take numerous forms, for example comprise an Intelor AMD type processor with various supporting chip circuitry, a MotorolaHC11 class Micro-controller is an excellent choice. The HC11 containsROM for the application program, system RAM, digital I/O and acommunications system. On the board (if desired) and external to theparticular micro controller chosen, is an EEROM 574, which may beemployed to store calibration, setup and configuration data. External tothe communications system is a multiplexer and driver circuit, e.g., anRS-485 transmitter and receiver 575 that allows the system to interfacewith other RS-485 devices on the main control board 555 and internalcontrol and power busses on other slave or daughter boards connected tothe system. As the name implies, the power I/O board also includes thesystem power supply and regulation module(s) 576 which rectify, filterand regulate selected line voltages (e.g., 24V A.C.) into usable DCpower for the entire system. Also, connected to the digital I/O of themicro controller 573 are TRIAC driver circuits 577 that switch thecontrol voltage (e.g., 24V A.C.) to the various contactors, relays andvalves in the system, and supply, as necessary, a pulse-width-modulated(PWM) output. For monitoring the system power fundamentals, i.e.,pressure, temperature, voltages and current, an analog signalconditioning circuit 578 applies analog signals to an analog to digital(A/D) converter 579 which in turn applies monitored and converted sensorinformation to the micro controller 573.

The clean in place (CIP) board 590 also operates as a slave board undercontrol of the main control board 555, and may be mounted as a daughterboard on the main control board 555. Turning now to FIG. 25, like thepower I/O board and other slave boards, the CIP board may also mount aseparate micro-controller 591 having its own onboard ROM for anapplication program, RAM and a UART for communications purposes. Samplemicro-controller types have already been provided above and theMotorolla HC 11 is also an excellent choice for this operational mode ofthe system. On the board (if desired) and external to the particularmicro controller chosen, is an EEPROM 592, which may be employed tostore calibration, setup and configuration data. External to the UART isan RS-485 transmitter and receiver 593 that allows the system tointerface with RS-485 devices on the power I/O board and internalcontrol and power bus. Inasmuch as the function of the CIP board is tofacilitate clean in place of the machine, also connected to the digitalI/O of the micro controller 591 are TRIAC driver circuits 594 thatswitch the control voltage (e.g., 24V A.C.) to the various contactors,relays and valves in the system, and supply, as necessary, apulse-width-modulated (PWM) output to control the mode of operationdescribed heretofore in the section of this specification entitled“Clean-In-Place Mode (CIP)”. As is conventional, the CIP board may mountthe local power supply and regulation module 595 which receives powerfrom the power I/O board and supplies local power for the CIP board.

Turning now to FIG. 26, the refrigerated control board 600 also operatesas a slave board under control of the main control board 555, and, likethe other boards, may be mounted as a daughter board on the main controlboard 555. However, once again, it is preferably of a distributedcontrol architecture where the processor is situated close to theactuator or sensor that it controls. Like the power I/O board and otherslave boards, the refrigerated control board 600 may also mount aseparate micro-controller 601 having its own onboard ROM for anapplication program, RAM and a UART for communications purposes. Samplemicro-controller manufacturers and types have already been providedabove and once again the Motorolla HC 11 is an excellent choice for thisoperational mode of the system. On the board (if desired) and externalto the particular micro controller chosen, is an EEPROM 602, which maybe employed to store calibration, setup and configuration data. Externalto the UART is an RS-485 transmitter and receiver 603 that allows thesystem to interface with RS-485 devices on the power I/O board andinternal control and power bus. Inasmuch as the function of therefrigeration and control board is to facilitate proper operation of therefrigeration system, also connected to the digital I/O of the microcontroller 591 are TRIAC driver circuits 604 that switch the controlvoltage (e.g., 24V A.C.) to the various contactors, relays and valves inthe system, and supply, as necessary, a pulse-width-modulated (PWM)output to control the operation described of the machine inrefrigerating, not only the finished product but maintenance of theproduct mix in the mix cabinet 43. This means that the refrigeratedcontrol board must control the passive refrigeration and refrigerantcontrol for proper operation of the temperature control in the mixcabinet 43. As is conventional, the refrigeration control board 600 maymount the local power supply and regulation module 605 which receivespower from the power I/O board and supplies local power for therefrigeration control board.

Turning now to FIG. 27, the data logging function is meant to be helpfulin maintaining the machine by monitoring its usage so that long termavailability, mean-time-between failure (MTBF) and product use and wastemay be monitored and acted upon when propitious to do so. As with theother daughter or slave boards connectable to the main board 555, onceagain, this board is preferably of a distributed control architecturetype where the processor is situated close to the actuator or sensorthat it controls. As with the boards previously described, the heart ofthe data logger (and communications) board 580 may be a micro-controlleror micro-processor 581. In the illustrated instance a micro-processor,for example of the 80486 class manufactured by Intel Corporation, may beemployed. Coupled to the micro-processor 581 is suitable ROM, in thepresent instance an EEPROM 592 which may store the application programfor the micro-processor. As is conventional, dynamic random accessmemory, DRAM 583 and standard BIOS (basic input/output scheme) ROM 584is also connected for providing active memory and stored system start upmemory for the data logger board 580. A UART 585 couples themicroprocessor 581 to an optically isolated RS-485 transmitter andreceiver 586 for “talking” with the main board 555. Recording andcommunication of data and events externally of the machine may beaccomplished in any convenient manner, in the illustrated instance byproviding a PCMCIA interface 587 which, through on-board sockets 587 a,587 b permits plug in of a first card 588 a (for example of flashmemory), or for a second card 588 b for insertion of a networking ormodem card. As shown, also located on the logger board 580 is a localpower supply and voltage regulation module 589 which is also coupled tothe internal control and power bus from the power I/O board 570.

Thus, the present invention provides numerous advantages with the closedrefrigeration system including a novel door and valve assembly forensuring good locking action and closing off of the freezing cylinderwhich not only ensures interlocking with and by the product dispenser,inadvertent displacement of the door is inhibited. Moreover, the coverdesign in association with the door provides prevention of condensation.The novel alignment features and sealing arrangement for the door givefurther advantages for capturing the door against the rim of thefreezing cylinder. Additionally, the rolling diaphragm construction ofthe product dispensing apparatus allows for maintenance of a cleanermachine.

While the invention has been described with a certain degree ofparticularity, it should be realized that the description and drawingsare meant to be in the way of example only, and numerous changes inconstruction and operation may be had without detracting or altering theinvention as hereinafter claimed.

What is claimed is:
 1. A door assembly for a freezing chamber, saidfreezing chamber comprising a tube having a rim at one end thereof, saiddoor assembly comprising; a door including alignment lugs on one of saiddoor and said rim and apertures, intended for reception of said lugs onthe other of said door and rim, to insure proper alignment of said doorwith said rim; an annular projection on one of said door and rim and anannular receptacle, aligned with said annular projection when the dooris in position in mating engagement with said rim, on the other of saiddoor and rim; and a Z-shaped, in cross section, seal fittable in saidreceptacle to receive said annular projection and to provide a sealtherewith; and a cover member, said cover member having an exterior andinterior portion, said interior portion having a door engagement portionto cause pressing engagement between said door and said rim, and alocking collar on the exterior portion of said cover for lockingengagement with the rim of said freezing tube, the major portion of saidinterior portion of said cover being spaced from said door to form aninsulating space.
 2. A door assembly for a freezing chamber inaccordance with claim 1 including a depending lip on said Z-shaped sealforming, with said annular projection, an axial seal.
 3. A door assemblyfor a freezing chamber in accordance with claim 2, including a secondlip on said Z-shaped seal forming another axial seal with saidprojection.
 4. A door assembly for a freezing chamber in accordance withclaim 3, including a connecting portion between said lips, forming withsaid projection a radial seal.
 5. A door assembly for a freezing chamberin accordance with claim 1 wherein said alignment lugs are of differentsize and mate only with correspondingly dimensioned alignment apertures.6. A door assembly for a freezing chamber in accordance with claim 1including a passageway in said door for receiving product from saidfreezing cylinder, and a product outlet from said door; a receptacle forinsertion into said door in a path aligned with said product outlet, anda product dispensing valve in said receptacle; and an aperture in saidcover aligned with said receptacle, and engageable thereby to retain andlock said cover to said door.
 7. A door assembly for a freezing chamberin accordance with claim 2 including a passageway in said door forreceiving product from said freezing cylinder, and a product outlet fromsaid door; a receptacle for insertion into said door in a path alignedwith said product outlet, and a product dispensing valve in saidreceptacle; and an aperture in said cover aligned with said receptacle,and engageable thereby to retain and lock said cover to said door.
 8. Adoor assembly for a freezing chamber in accordance with claim 7 whereinsaid alignment lugs are of different size and mate only withcorrespondingly dimensioned alignment apertures.
 9. A door assembly fora freezing chamber in accordance with claim 6, wherein said dispensingvalve includes a piston and a seat for said piston in said door in saidproduct outlet; and a rolling diaphragm carried by said piston to sealthe receptacle from product whether the piston is either in a positionto dispense product or is sealing the product outlet.
 10. A dispensingvalve assembly for dispensing a softserve product from a refrigerationmachine, said valve assembly comprising; a receptacle and a cup shapedinsert, below said receptacle, said insert having a skirt, a shaftextending through said receptacle and insert and guided thereby; a headpositioned on the extended end of said shaft and captured thereby and adiaphragm connected to said head end and circumscribing said skirt ofsaid insert, whereby when said shaft reciprocates, said diaphragm rollsinwardly of the skirt of said insert thereby inhibiting product mix fromentering the receptacle and insert through which said shaft portion ofsaid valve extends; a door assembly for said softserve freezing machine,said door assembly including a cover; an aperture in said cover forreceiving a valve body of said dispensing valve assembly, and meansassociated with said valve assembly for locking said valve assembly tosaid cover; and a door coupled to said cover and dispensing valve forcoupling to a freezing cylinder of said softserve machine.
 11. Adispensing valve assembly for dispensing a softserve product from arefrigeration machine in accordance with claim 10 including a productdraw handle associated with the shaft for effecting reciprocationthereof.
 12. A dispensing valve assembly for dispensing a softserveproduct from a refrigeration machine in accordance with claim 10,including one of alignment lugs and apertures on said door for matingalignment with one of mating apertures or alignment lugs on the freezingchamber.
 13. A dispensing valve assembly for dispensing a softserveproduct from a refrigeration machine in accordance with claim 12 whereinsaid alignment lugs are of different size and mate only withcorrespondingly dimensioned alignment apertures.
 14. A combination doorand semi-frozen food product dispensing valve assembly for a softserverefrigeration machine; said machine including a closed refrigerationsystem with a recirculating refrigerant path, said system including acondenser in said path having a liquid refrigerant output, a throttlingexpansion valve for changing state of liquid refrigerant to a gas and anevaporator having an inlet and an outlet, all serially connected in saidrefrigerant path; said evaporator including a freezing chamber thereinfor receiving product mix and dispensing semi-frozen product through anoutlet end of said freezing chamber; a circumferentially extending rimon said freezing chamber, and a door in said combination door and valveassembly for mating in sealing engagement with said rim; a coverassociated with said door and a locking ring associated with said cover,and means on said locking ring for engaging said rim and urging saiddoor against said rim in sealing engagement therewith; a valve assemblyfor engagement in said door assembly with said door, through said cover,locking said door to said rim inhibiting displacement of said cover; afrozen product passageway in said door assembly and said valve assembly,and a dispensing valve shaft in said valve assembly movable between afirst position closing off said passageway for product and to a secondposition opening said passageway to permit product to pass therethrough.15. A combination door and semi-frozen food product dispensing valve fora softserve refrigeration machine in accordance with claim 14 whereinsaid valve assembly includes; a receptacle and a cup shaped insert,below said receptacle, said insert having a skirt, said shaft extendingthrough said receptacle and insert and guided thereby; a head positionedon the extended end of said shaft and captured thereby and a diaphragmconnected to said head end and circumscribing said skirt of said insert,whereby when said shaft moves between its first and second positions,said diaphragm rolls inwardly of the skirt of said insert therebyinhibiting product mix from entering the receptacle and insert throughwhich said shaft extends.
 16. A combination door and semi-frozen foodproduct dispensing valve for a softserve refrigeration machine inaccordance with claim 15 including a product draw handle associated withthe shaft for effecting reciprocation thereof between said first andsecond positions.
 17. A combination door and semi-frozen food productdispensing valve for a softserve refrigeration machine in accordancewith claim 16 including a biasing spring for restoring said shaft to itsrest position.
 18. A combination door and semi-frozen food productdispensing valve for a softserve refrigeration machine in accordancewith claim 15 including a circumferentially extending recess in one ofsaid door and rim, a mating projection on the other of said door andrim, and a compressible seal intermediate said projection and saidrecess to effect a seal between said door and said rim.
 19. Acombination door and semi-frozen food product dispensing valve for asoftserve refrigeration machine in accordance with claim 18 herein saidseal is Z-shaped in cross section.
 20. A combination door andsemi-frozen food product dispensing valve for a softserve refrigerationmachine in accordance with claim 14 wherein said locking ring isintegral with said cover, and at least a portion of said cover is spacedfrom said valve assembly to form an insulator therebetween.